WASHINGTON (AP) -- The San Diego Padres had one of those nights where just about nothing went right -- except perhaps for Jedd Gyorko, who hit two home runs.

Manager Pat Murphy was ejected, James Shields barely avoided injury on the last of his 121 pitches and the Padres succumbed to the Washington Nationals 8-3 Tuesday night.

Murphy was tossed after arguing that a ball hit by Nationals slugger Bryce Harper in the sixth inning should have been called fair, but instead was ruled foul. Harper ultimately drew a walk, and two batters later Ryan Zimmerman hit a clinching grand slam.

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"Umpires miss calls, coaches miss calls," Murphy said. "It's unfortunate because it played a role."

Shields wasn't much happier, even though Zimmerman's drive came off Bud Norris.

"I mean, that's a terrible call. There's no doubt about it," the pitcher said. "The ball was two feet in front of him and he was acting like it hit him."

Harper skirted the issue, saying only, "I'm just glad Zim hit the homer and we got four runs."

It was the second straight loss for San Diego following five straight wins. Adding to the misery: Matt Kemp's 15-game hitting streak ended and Justin Upton failed to reach base for the first time in 19 games.

Shields (9-6) gave up four runs, eight hits and four walks in 5 2/3 innings. San Diego has lost 12 of his 15 starts since June 9.

He left after a comebacker struck his foot in the sixth, but he survived that -- and the 121-pitch performance.

"I felt like my stuff was all right tonight," Shields said. "It was just a matter of, they were taking good pitches and were hitting pitches that normally you get outs on."

Stephen Strasburg (8-6) struck out seven in six innings for Washington. The right-hander retired the final 15 batters he faced following a second-inning homer by Gyorko.

Strasburg is 5-1 with a 1.51 ERA in his last seven starts and 5-1 in his career against the Padres.

Zimmerman drove a 2-0 pitch into the seats beyond the right-field wall for an 8-2 lead. It was his fifth career slam, the first since 2013.

Murphy was tossed one inning later because he couldn't abandon his contention that the ball called four was really fair.

"It was not the correct call," the manager said. "But like I said, those things happen. It's our responsibility to get the next guy out, and the next guy out and the next guy out."

After Gyorko put the Padres up 2-0 with a two-run drive, Wilson Ramos tied it in the bottom of the second with his 11th home run, the second in two games following a 22-game drought.

Yunel Escobar hit an RBI double for Washington in the third, and doubles by Harper and Ian Desmond made it 4-2 in the fifth.

It was 8-3 before Gyorko connected off Casey Janssen in the seventh. It was Gyorko's third career multihomer game, the first this season.

TRAINER'S ROOM

Padres: Murphy said Bud Norris has been nursing a "little adductor strain" and will be examined.

Nationals: Span will work his way back slowly before playing on a daily basis, manager Matt Williams said.

ON DECK

Padres: Winless in his last three starts, Tyson Ross (8-9, 3.22 ERA) seeks his first victory since Aug. 3 on Wednesday night.

Nationals: Gio Gonzalez (9-6, 3.98 ERA) has allowed 11 runs and 13 hits in his last two starts. He and Ross were teammates in Oakland in 2010-11.